Means for automatic closing of punctures in pneumatic tires.



J. LINDHARTH. MEANS FOR AUTOMATIC CLOSING 0F PUNGTURES INP1\IEU]S(IA'1IG TIRES.

APPLICATION FILED NOV.27, 1907.

Patented Dec. 22, 1908 W messes 7 l2 veal/x7" d JZZZZ0 zz'izdag ih RSco., WASHINGYON, uc JULIUS LINDHARTH, OF COPENHAGEN, DENMARK.

MEANS FOR AUTOMATIC CLOSING OF PUNCTU'RES IN PNEUMATIC TIRES.

Application filed November 27, 1907.

Specification of Letters Patent.

Patented Dec. 22, 1908.

Serial No. 404,195.

To all whom it may concern:

Be it known that I, JULIUs LINDHARTH, subject of the King of Denmark,and a resident of Copenhagen, Denmark, Aaboulevarden 6, engineer, haveinvented new and useful Improvements in Means for Automatic Closing ofPunctures in Pneumatic Tires, of which the following is a specification.

The present invention has for its object an improved arrangement andmethod for the automatic closing of punctures in pneumatic tires ofcycles, automobiles and other vehicles, and the like, caused either byinvoluntary damage during the riding or by wilful injury. To attainthis, several means have been proposed, but none of these has so farfound application in practice, presumably mainly because they have beenineffective against more serious injuries. There has been proposed theuse of various liquid adhesive compounds to be introduced in the airtube, the idea being that part thereof would be driven out, along withthe escaping air, into the hole roduced in the tube, thereby closing theho e. Further it has been proposed to add to such fluid compound in theair tube certain more or less finely ground or fibrous substances, inorder to enhance the closing effect. Or it has been proposed, on thestrip of the outer face of the tube which is particularly exposed topunctures during the riding, to paste a tape, the object being tocounteract on this strip the elasticity of the tube, and thereby tocause a puncture, here efiected, to remain in a capillary state andtherefore likely to be closed simply by the formation of a film ofliquid therein. Finally it has been proposed to apply the adhesive fluidon the outside of the tube, in combination with a fibrous substanceserving as absorbing agent for the said fluid.

According to the present invention the problem is solved by introducinginto the tube an adhesive fiuid of suitable composition and consistencyand enveloping the tube by a loosely fitting bandage consisting of asoft, non-elastic and fibrous substance.

In the accompanying drawings I have shown, by way of example, how myinvention may be carried into effect.

Similar characters of reference indicate corresponding parts in all theviews.

Figure 1 shows in cross-section the air tube and the parts employed toproduce its handage. Fig. 2 shows, also in cross section, the tube withthe bandage applied, and Fig. 3

evaporation may freely take place.

shows, also in cross-section, the finished tube placed on the rim andprotected by the usual rubber cover.

Referring now to the drawings a indicates the moderately inflatedtube, 1) a strip of fibrous substance, such as cotton, wool or wadding,sufficiently long to reach entirely around the tube s periphery and wideenough to cover its sectional outline, and c is a strip of shirting,muslin or other suitable material, somewhat longer and wider than thestrip 6, and having its edges d coated by rubber solution or the like.

When the tube is moderately inflated, the strip 1) is applied around itand is, in its turn, covered by the strip 0, whose edges are thenpressed together and thereby pasted to one another. This arrangement isof such nature that the pasting together will not hinder the inflationof the tube, as the joint will simply yield and expand a little, if themuslin strip happens to be tightened too much around the band of fibroussubstance. The finished bandaged tube has then the appearancerepresented in Fig. 2 and may now, in the usual manner, be placed inposition on the wheel rim 6 and covered by the tire f (Fig. 3).

The viscous fluid may be introduced into the inner tube through thevalve seat, after the valve plug has been removed and this of course maybe done either before or after the tube is placed in position on thewheel. necessary requirements for the fluid are that it shall moistenthe rubber tube, adhere and partly evaporate on its outer face whereStill it must not be apt to dry up completely, i. c. it must retain acertain softness and elasticity, so that the partly dried fluid film orskin formed over and around a puncture may follow the expansions andcontractions of the tube without cracking or separating therefrom orotherwise being injured. Further it must not consolidate at ordinarywinter temperature and must not be subject to any chemical alteration,nor be influenced by or influence the rubber, and it must be so viscousthat during the alternate rotation and rest of the wheel it will remaindistributed as a thin film throughout the inside of the tube, and not,when the cycle is at rest, entirely collect at a single point of thetube. A fluid answering these requirements may preferably be composed ofdeXtrin (burnt starch), water, glycerin and a little alcohol The or thelike in suitable proportions, and I have found that for instance 200parts by weight of dextrin, 150 parts of water, 3 parts of glycerin and4 parts of absolute 5 alcohol form an especially suitable com pound. Ihave further found that with very great advantage there may be added tothe fluid certain finely powdered sub stances whereto it readily sticks,such as sawdust or ground wood, because such substance when beingintroduced into the puncture together with the fluid will most elficiently close the puncture.

Of the above mentioned compound I v introduce into an ordinary bicycletire from 8% to 5:}; ounces.

The substance used for the bandage I) outside of the tube must be looseand soft and not much elastic, and preferably of fibrous or threadytexture. Its object is to act by being pressed into the tube togetherwith the implement causing the puncture, and it must not then, by itsown elasticity, tend to draw itself out of the hole again, when thewounding implement is removed from the tube. Further it must not betightly stretched around the tube, nor pasted thereto, as in that caseit would hinder the full inflation of the tube, and finally it must notabsorb to any material degree, the fluid contained in the tube, as itwould then allow the fluid to percolate through the puncture, withoutforcing it to expand on the outside of the tube, thereby forming a skinor plaster adhering to the tube and covering the hole.

On the other hand, the fluid must act adhesively on the fibroussubstance, actually causing its threads to adhere to the tube in andaround any hole produced therein. Of the substances answering therequirements mentioned we have found non-hygroscopic cotton to beparticularly suitable, especially the commercial sheet wadding. We havefound that the cotton wadding may to advantage be impregnated withparaffin oil, it being immersed for instance in a mixture of 1 partweight of paraffin oil and 8 parts of benzin and then wrung; whereby itbecomes suitably non-hygroscopic and attains a certain tough softness,so as not to be worn or ground to pieces during the riding.

For the outer covering may be used any suitable thin and strong fabric,for instance muslin, shirting or the like, with or without sizing. Eventough paper may be used for this purpose.

The tube treated according to my invention will act in the followingmanner. If a flint chip, for instance, a horse shoe nail or the like, ispressed up through the outer covering and enters through the pneumatictube, then it will carry along with it into the hole a tuft of thefibrous layer. When the wounding body is removed, the fibers pressed inwill remain in the hole and the small amount of air, if any, escapingthrough the hole will at once introduce some of the adhesive liquidtherein, and this liquid will then close up all the interstices betweenthe fibers and the walls of the punctured hole, thereby instantlyhealing the latter. A bit of the liquid will percolate along the surfaceof the tube, there solidifying in combination with the nearest fibersand forming an air tight elastic crust or skin of thready structurecovering the hole. As the fibrous layer is non-absorbent, there is nodanger of the fluid extending further out through the fibrous layer,thereby on the one hand causing the crust or skin to become too soft andon the other hand perhaps causing the l uid to penetrate all the way outto the inside of the outer cover, thus gluing the latter to the fibrouslayer.-

Air tubes protected according to my invention have proved perfectlyinvulnerable, even when treated as violently as when being pierced by apocket knife, and the superiority of my method of protection over theabove mentioned heretofore proposed treatments is especially great insuch violent and serious injury. This is mainly due to the fibrous layerbeing located outside of the tube and the fluid inside of the same, asby such arrangement the dry fibrous layer will be pressed into the holeproduced, while the air will press the fluid into the hole. If, on theother hand, the fibrous layer and the liquid both were located outsideof the tube, then the liquid would be blown, by the escaping 10o air,away from the walls of the hole, and besides there must necessarily beused a tight inclosure outside of the fibrous layer, in order to preventthe liquid from coming into contact with the inner side of the outertube or cover and thereby pasting the fibrous layer thereto.

Another reason for the superiority of the protection afforded by thisinvention is that the fibrous layer is of loose, soft and rathernon-elastic texture, so that it has no tendency to resist its ownintroduction, together with the wounding implement, through the wall ofthe tube, and further is not likely to slip out again from the hole,when the implement is drawn out, or when acted upon by the air pressure.

A final advantage is that the fibrous layer may be applied very looselyaround the tube, without being pasted to its surface, and it may thus bemade to encircle the entire tube surface without diminishing its abilityto freely expand and contract elastically.

What I claim, and desire to secure by Letters Patent,- is:

1. A means for preventing injury to vehiole tires by punctures etc.consisting of a soft fibrous non elastic covering for the inner tube, anon-elastic covering over the fibrous material, and a solution withinthe inner 130 tube composed of 200 parts of clextrin, 150 material, anda solution Within the inner parts of Water, 3 parts of glycerin, and 4tube composed of 200 parts of dextrin, 150 parts of absolute alcohol,and sawdust, the parts of Water, 3 parts of glycerin, 4 parts of saidfibrous covering being permeated with a absolute alcohol, and sawdust.

5 solution consisting of 1 part of parafiin oil, Signed by me atCopenhagen, Denmark 15 1 and 8 parts of benzin. this 28th day of October1907.

2. A means for preventing injury to vehi- JULIUS LlNDHARTHl cle tires bypuncture, etc., consisting of a Witnesses: soft fibrous non-elasticcovering for the inner OTTO WIEsEMANN,

1O tube, a non-elastic covering over the fibrous I GEO. H. EMSLIE.

